<div id="app">
  <h1 ref="h1">{{ title }}</h1>
</div>
<script src="https://unpkg.com/vue@3"></script>
<script>
  const { createApp, nextTick } = Vue
  createApp({
    data() {
      return {
        title: 'nextTick'
      }
    },
    mounted() {
      this.title = 'abc'
      this.$refs.h1.innerText // 'nextTick'
      nextTick(() => {
        this.$refs.h1.innerText // 'abc'
      })
    }
  }).mount('#app')
</script>